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प्रश्न
Write the mechanism of acid-catalysed dehydration of ethanol to yield ethene.
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उत्तर
In the presence of conc. acids such as H3PO4 and H2SO4 alcohols undergo dehydration to yield alkenes.
\[\ce{\underset{Ethanol}{H3C - CH2 - OH} ->[conc{.} H+/\Delta] \underset{Ethene}{CH2 = CH2} + H2O}\]
The mechanism for this reaction is:
Step 1: Protonation of ethanol:
Step 1: Formation of carbocation:
Step 3: Formation of ethene and regeneration of proton:
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संबंधित प्रश्न
Give the equation of the following reaction:
Dilute HNO3 with phenol.
Name the reagent used in the following reaction:
Benzyl alcohol to benzoic acid.
When 3-methylbutan-2-ol is treated with HBr, the following reaction takes place:
\[\begin{array}{cc}
\phantom{...................................}\ce{Br}\\
\phantom{..................................}|\\
\ce{CH3 - CH - CH - CH3 ->[HBr] CH3 - C - CH2 - CH3}\\
|\phantom{.........}|\phantom{...................................}|\phantom{...........}\\
\ce{CH3}\phantom{...}\ce{OH}\phantom{...............................}\ce{CH3}\phantom{.......}\\
\end{array}\]
Give a mechanism for this reaction.
(Hint: The secondary carbocation formed in step II rearranges to a more
stable tertiary carbocation by a hydride ion shift from 3rd carbon atom.)
Write the mechanism (using curved arrow notation) of the following reaction :
Lucas test is used for the detection of _____________.
In the reduction \[\ce{R - CHO + H2 -> RCH2OH}\] the catalyst used is:
Which of the following are used to convert RCHO into RCH2OH?
(i) H2/Pd
(ii) LiAlH4
(iii) NaBH4
(iv) Reaction with RMgX followed by hydrolysis
Dehydration of 2-butanol yields:
Lucas test is done to differentiate between ____________.
\[\ce{CH3CH2OH}\] can be converted into \[\ce{CH3CHO}\] by ______.
Identify the secondary alcohols from the following set:
- \[\ce{CH3CH2CH(OH)CH3}\]
- \[\ce{(C2H5)3COH}\]
Mark the correct increasing order of reactivity of the following compounds with HBr/HCl.
| (a) |  |
| (b) |  |
| (c) |  |
What is Lucas reagent?
The correct geometry around oxygen in CH3OCH3 is
Which of the following observation is shown by 2-phenyl ethanol with Lucas Reagent?
Write the mechanism of acid dehydration of ethanol to yield ethene.
Write the mechanism of acid dehydration of ethanol to yield ethene.
